#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
int main()
{
	int a = 0;
	int cnt = 0;
	for (a = 1; a <= 100; a++)
	{
		if ((a % 10) == 9 || (a >=90 && a < 99))
		{
			cnt++;
		}
	}
	printf("%d", cnt);
	return 0;
}